gallium: add start_slot parameter to set_vertex_buffers

This allows updating only a subrange of buffer bindings.

set_vertex_buffers(pipe, start_slot, count, NULL) unbinds buffers in that
range. Binding NULL resources unbinds buffers too (both buffer and user_buffer
must be NULL).

The meta ops are adapted to only save, change, and restore the single slot
they use. The cso_context can save and restore only one vertex buffer slot.
The clients can query which one it is using cso_get_aux_vertex_buffer_slot.
It's currently set to 0. (the Draw module breaks if it's set to non-zero)

It should decrease the CPU overhead when using a lot of meta ops, but
the drivers must be able to treat each vertex buffer slot as a separate
state (only r600g does so at the moment).

I can imagine this also being useful for optimizing some OpenGL use cases.

Reviewed-by: Brian Paul <[email protected]>

1 files changed, 1 insertions, 1 deletions

diff --git a/src/gallium/state_trackers/vega/renderer.c b/src/gallium/state_trackers/vega/renderer.c
index de13458e384..9faf54f411d 100644
--- a/src/gallium/state_trackers/vega/renderer.c
+++ b/src/gallium/state_trackers/vega/renderer.c
@@ -1040,7 +1040,7 @@ void renderer_polygon_stencil(struct renderer *renderer,
 {
    assert(renderer->state == RENDERER_STATE_POLYGON_STENCIL);
 
-   cso_set_vertex_buffers(renderer->cso, 1, vbuf);
+   cso_set_vertex_buffers(renderer->cso, 0, 1, vbuf);
 
    if (!renderer->u.polygon_stencil.manual_two_sides) {
       cso_draw_arrays(renderer->cso, mode, start, count);